Composition comprising fluorinated, radiation-curable dyes for surface energy control

ABSTRACT

A radiation-curable composition having a reduced surface energy and including a reactive dye containing at least one radiation-curable substituent and at least one fluorine-containing substituent. The reactive dye may include any anthraquinone, methine, azo, azine, or xanthene dye adapted to contain at least one radiation-curable substituent and at least one fluorine-containing substituent. The radiation-curable substituent may include (meth)acrylate, styrene, vinyl ether, vinyl ester, N-substituted acrylamide, N-vinyl amide, maleate ester, and fumarate ester.

FIELD OF THE INVENTION

The present invention relates to a radiation-curable composition havinga reduced surface energy. In particular, the composition comprises areactive dye comprising at least one radiation-curable substituent andat least one fluorine-containing substituent. The composition isadaptable for a variety of uses, including, for example, as a coloredcoating for optical fiber, as well as a coating, ink or colorant packagein the printing and inking industries.

BACKGROUND OF THE INVENTION

Compositions containing fluorinated chemical compounds are known in theart.

For example, U.S. Pat. No. 5,567,794 to Barraud, et al. discloses afluorinated acrylate type polymeric material for coating optical fibersbased on at least one diol, a diisocyanate, and an acrylate, wherein atleast one of the diol, diisocyanate, and acrylate contains fluorine andat least one of the diol, diisocyanate, and acrylate contains sulfur.The '794 patent, however, does not disclose or suggest a compositioncomprising a reactive dye comprising at least one radiation-curablesubstituent and at least one fluorine-containing substituent.

U.S. Pat. No. 5,541,235 to Busman, et al. relates to a cationic dyecompound and a method for increasing its solubility in organic solventsby associating it with fluorinated alkylsulfonyl anions. The '235 patentdoes not disclose or suggest a reactive dye comprising at least oneradiation-curable substituent and at least one fluorine-containingsubstituent.

U.S. Pat. No. 6,133,472 to Nalewajek, et al. relates to fluorinatedvinyl ethers and, more particularly, to fluorinated compounds containingone or more oxyvinyl groups. The '472 patent does not disclose orsuggest a composition comprising a reactive dye comprising at least oneradiation-curable substituent and at least one fluorine-containingsubstituent.

Indeed, some fluorinated dyes are known to be useful in biologicalapplications in which a highly sensitive detection reagent is desirable.For example, U.S. Pat. No. 6,229,055 to Klaubert, et al. disclosesfluorinated xanthene dyes and dye-conjugates suitable for use astracers, labels, or synthetic intermediates. The '055 patent, however,does not disclose or suggest a radiation-curable composition comprisinga reactive dye comprising a radiation-curable substituent and afluorine-containing substituent.

SUMMARY OF THE INVENTION

The present invention provides a radiation-curable compositioncomprising a reactive dye comprising at least one radiation-curablesubstituent and at least one fluorine-containing substituent. Theradiation-curable composition has a reduced surface energy. Theradiation-curable composition may be adapted to serve a variety ofpurposes. For example, the composition may be formulated to serve as aprotective, colored coating for substrates manufactured from a widevariety of materials, including, for example, glass, plastic, ceramic,metal and wood.

DETAILED DESCRIPTION OF THE INVENTION

The radiation-curable composition of the present invention is notparticularly limited by how it is prepared. Any conventional process andequipment suitable for this purpose may be employed. Blends ofoligomers, monomer diluents, and other ingredients in the art ofradiation-curable compositions may also be included within thecomposition to tailor the composition's properties.

A characteristic feature of the present composition is its reducedsurface energy. For example, when the composition is adapted for use asa coating, the reactive dye of the composition orients itself to theupper microns of the coating surface, thereby concentrating the dye inthe outer area of the coating. The result is a coating that exhibits areduced surface energy without the addition of a release agent orsurface agent. In addition, the concentration of dye at the outersurface of the coating results in a reduced amount of dye that is neededto color a substrate. Finally, coating the present composition onto thesurface of a substrate yields a coated surface that is water repellent,easy to clean, and relatively releasable. For example, an optical fibercoated with the composition spools easier.

The radiation-curable composition is now described in more detail.

The radiation-curable composition comprises a reactive dye comprising atleast one radiation-curable substituent and at least onefluorine-containing substituent. The reactive dye of the composition maybe any chromophore-containing compound that also contains at least oneradiation-curable group, e.g., a radiation-curable substituent, andfluorine, e.g., a fluorine-containing substituent. For example, thereactive dye of the composition may be aradiation-curable-group-substituted, fluorine-substituted derivative ofan anthraquinone dye, a methine dye, an azo dye, an azine dye, or axanthene dye.

The reactive dye of the composition is not limited by molecular weight.For example, a starting material for producing the reactive dye of thecomposition may be any of the so-called oligomeric dyes, provided thatit may be adapted to contain fluorine and at least one radiation-curablegroup, e.g., ethylenic unsaturation, such as acrylate. Alternatively,the starting material for producing the reactive dye of the compositionmay be any of the so-called monomeric dyes, provided that it too may beadapted to contain fluorine and at least one radiation-curable group,e.g., ethylenic unsaturation, such as acrylate.

In certain embodiments, the at least one radiation-curable substituentwill be separate and apart from the at least one fluorine-containingsubstituent. Thus, in certain embodiments, the chromophore-containingcompound will have a total of at least two substituents, one substituentbeing a radiation-curable substituent and the other substituent being afluorine-containing substituent. The fluorine-containing substituent maysimply be fluorine or it may be any substituent comprising fluorine.

In other embodiments, the chromophore-containing compound may have oneor more substituents, but at least one substituent will contain bothfluorine and a radiation-curable moiety.

The chemical nature of a radiation-curable compound that may be reactedto provide a radiation-curable substituent on the reactive dye of theinvention is not narrowly limited, provided that it contains afunctional component that can be reacted to provide the dye with theradiation-curable substituent.

Isocyanate chemistry is a general example of a method for providing adye of this invention with a radiation-curable substituent. By reactingan isocyanate-reactive dye and an isocyanate-reactive radiation-curablecompound with a diisocyanate, for example, aradiation-curable-group-containing dye can be formed. Alternatively, anisocyanate-reactive dye may be reacted with an isocyanate, including amonoisocyanate, containing radiation-curable functionality, e.g.,ethylenic unsaturation, such as an acrylate group, in order to form theradiation-curable-group-containing dye. While further detail will beprovided below for arriving at a dye according to this invention viaisocyanate chemistry, it will be readily understood by one of ordinaryskill in the art that a dye according to the invention may be preparedby any and all reaction chemistries that lead to aradiation-curable-group-containing, fluorine-containing dye.

An example of an isocyanate-reactive dye is a chromophore-containingcompound having one or more hydroxy substituents. Suitablechromophore-containing compounds having one or more hydroxy substituentsare marketed under the trademark REACTINT™ by the Milliken ChemicalCompany. Alternatively, the isocyanate-reactive dye may be anychromophore-containing compound having one or more thiol or aminosubstituents.

Examples of suitable diisocyanates include 1,3-cyclopentenediisocyanate, 1,4-cyclohexane diisocyanate, 1,3-cyclohexanediisocyanate, 3-isocyanatemethyl3,5,5-trimethylcyclohexyl isocyanate(isophorone diisocyanate or IPDI), 4,4′-methylenebis(cyclohexylisocyanate) (H₁₂MDI or DESMODUR W), methyl-2,4-cyclohexane diisocyanate,methyl-2,6-cyclohexane diisocyanate, and 1,3- or 1,4-bis(isocyanatemethyl)cyclohexane.

The radiation-curable compound may be any hydroxy-, thiol-, oramino-functionalized, i.e. any isocyanate-reactive, compound capable ofpolymerizing under the influence of, for example, ultraviolet radiation.

One type of radiation-curable functionality is, for example, ethylenicunsaturation, which in general is polymerized through radicalpolymerization, but can also be polymerized through cationicpolymerization. Groups containing (meth)acrylate, styrene, vinylether,vinyl ester, N-substituted acrylamide, N-vinyl amide, maleate ester, andfumarate ester moieties are examples of a suitable radiation-curablecompound.

Preferred isocyanate-reactive radiation-curable compounds that react toprovide the radiation-curable substituent are hydroxy-functional(meth)acrylates. Examples of hydroxy-functional (meth)acrylates include2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate,2-hydroxybutyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate,pentanediol mono(meth)acrylate, 2-hydroxy-3-phenyloxypropyl(meth)acrylate, 2-hydroxyalkyl(meth)acryloyl phosphate,4-hydroxycyclohexyl (meth)acrylate, cyclohexanedimethanolmono(meth)acrylate, neopentyl glycol mono(meth)acrylate,trimethylolpropane di(meth)acrylate, and pentaerythritoltri(meth)acrylate.

Another type of radiation-curable functionality is provided by, forexample, epoxy groups, or thiol-ene or amine-ene systems. Epoxy groups,in general, can be polymerized through cationic polymerization, whereasthe thiol-ene and amine-ene systems are usually polymerized throughradical polymerization. The epoxy groups may be, for example,homopolymerized. In the thiol-ene and amine-ene systems, for example,polymerization may occur between a group containing allylic unsaturationand a group containing a tertiary amine or thiol.

For embodiments wherein the chromophore-containing compound has onesubstituent that contains both fluorine and a radiation-curable moiety,the radiation-curable compound that reacts to provide aradiation-curable substituent on the reactive dye of the invention is afluorinated radiation-curable compound. Fluorinated radiation-curablecompounds that may be reacted to provide a fluorinated,radiation-curable substituent on a chromophore-containing compound maybe purchased from Fluorochem, USA, and include compounds such as:3-(perfluorobutyl)-2-hydroxy propylacrylate;3-(perfluoro-n-hexyl)propyl-2-ene-1-ol;3-(perfluoro-7-methyloctyl)2-hydroxypropylmethylacrylate;3-(perfluorooctyl)-2-hydroxypropyl acrylate; 2,3,4 trifluorocinnamicacid; and 4,4,4-trifluorocrotonic acid. Of course, the foregoing list isnot exclusive, and one skilled in the art may envision a number ofstructures containing both fluorine and radiation-curable, e.g.,uv-curable, functionality.

Prior to being substituted with a radiation-curable substituent,regardless of whether the radiation-curable substituent is itselffluorinated, the reactive dye of the composition may be fluorinated byany method known in the art. Alternatively, the reactive dye may befluorinated by any method known in the art after it has been substitutedwith a radiation-curable substituent, again regardless of whether theradiation-curable substituent is itself fluorinated.

As mentioned earlier, fluorinated dyes are known, and any method offluorination may be employed, including the method described in U.S.Pat. No. 6,229,055 to Klaubert, et al., which is incorporated herein inits entirety. Examples of fluorinated dyes that, when provided with aradiation-curable group, may be suitable for use in the presentinvention, include dyes produced by BASF, Ciba Specialty Chemicals, ICI,and Bayer. They may be found under the trade names PROCION MX, BASILENM, CIBACRON, CIBACRON E, LEVAFIX E-N, and DRIMAREN K.

The radiation-curable composition may also comprise a radiation-curableoligomer, for example, a urethane (meth)acrylate oligomer. The oligomermay be synthesized by methods known in the art or purchasedcommercially. A suitable method of synthesizing a radiation-curableoligomer for use in the present composition is set forth in U.S. Pat.No. 6,323,255, which is incorporated herein in its entirety.

The radiation-curable composition may also comprise a photoinitiator,such as, for example, a free radical photoinitiator. Suitable freeradical-type photoinitiators include, for example, an acyl phosphineoxide photoinitiator, more specifically, a benzoyl diaryl phosphineoxide photoinitiator. Examples of suitable benzoyl diaryl phosphineoxide photoinitiators include:bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide (Irgacure 819 availablefrom Ciba Additives), (2,4,6-trimethylbenzoyl)diphenylphosphine oxide(Lucerin TPO available from BASF of Parsippony, N.J.);bis(2,6-dimethoxybenzoyl)-2,4,4-trimethylpentylphosphine oxide, which isa first component (25 wt %) of Irgacure 1700 available from CibaAdditives, Tarrytown, N.Y. The second component (75 wt %) of Irgacure1700 is 2-hydroxy-2-methyl-1-phenylpropane-1-one.2-hydroxy-2-methyl-1-phenylpropane-1-one is also available as anindividual photoinitiator named Darocur 1173. Further examples of freeradical-type photoinitiators include: hydroxycyclohexylphenylketone;hydroxymethylphenylpropanone; dimethoxyphenylacetophenone;2-methyl-1-[4-(methylthio)phenyl]-2-morpholino propan-1-one;1-(4-isopropylphenyl)-2-hydroxy-2-methylpropan-1-one;1-(4-dodecylphenyl)-2-hydroxy-2-methylpropan-1-one;4-(2-hydroxyethoxy)phenyl-2(2-hydroxy-2-propyl)-ketone; diethoxyphenylacetophenone; 2,4,6-trimethylbenzoyl diphenylphosphone; and mixtures ofthe foregoing.

A single reactive diluent or mixture of reactive diluents may beincluded in the radiation-curable composition. While not wishing to bebound by theory, it is theorized that, during the polymerization of theurethane acrylate oligomer, the reactive diluent(s) hooks togetherchains of the urethane acrylate oligomer. Adequate curing is promoted bythe presence of the reactive diluent(s). The reactive diluent alsofunctions as a solvent for the urethane acrylate oligomer. The use ofthe reactive diluent(s) allows the formulator to adjust the viscosity ofthe solution to improve processability.

The reactive diluent(s) may, for example, be a lower molecular weight,liquid acrylate-functional compound including the following diacrylatesand monofunctional acrylates: tridecyl acrylate, 1,6-hexanedioldiacrylate, 1,4-butanediol diacrylate, ethylene glycol diacrylate,diethylene glycol diacrylate, tetraethylene glycol diacrylate,tripropylene glycol diacrylate, neopentyl glycol diacrylate,1,4-butanediol dimethacrylate, poly(butanediol) diacrylate, tetrathyleneglycol dimethacrylate, 1,3-butylene glycol diacrylate, tetraethyleneglycol diacrylate, triisopropylene glycol diacrylate, triisopropyleneglycol diacrylate, ethoxylated bisphenol-A diacrylate, and isobornylacrylate. Another example of a reactive diluent is n-vinyl caprolactam.

The radiation-curable composition may include an adhesion promoter.Examples of adhesion promoters include acid functional materials andorganofunctional silanes. For example, the organofunctional silane maybe an amino-functional silane, an acrylamido-functional silane, amercapto-functional silane, an allyl-functional silane, avinyl-functional silane, a methylacrylate-functional silane, and anacrylate-functional silane. The organofunctional silane may bemercaptoalkyl trialkoxyl silane, a methacryloyxlalkyl trialkoxy silane,an aminoalkyl trialkoxyl silane, a vinyl trialikoxyl silane,3-aminopropyltriethoxy silane, 3-methacryloxypropyltrimethoxy silane,gamma-mercaptopropyltrimethoxy silane, gamma-mercaptopropyl(gamma-mercaptopropyl)triethoxy silane,beta-(3,4-epoxycyclohexyl)ethyltrimethoxy silane,gamma-glycidoxypropyltrimethoxy silane, 3-vinylthiopropyltrimethoxysilane, vinyl-tris-(beta-methoxyethoxy) silane, vinyl triacetoxy silane,and mixtures thereof. A particular adhesion promoter is KBM 803available from Shin-Etsu Silicones of America, Inc, of Torrance, Calif.

The radiation-curable composition may also include each of the followingwell-known additives: antioxidants, flow control agents, sensitizers,stabilizers, lubricants and wetting agents.

In a preferred embodiment, however, the radiation-curable composition isfree of release agents or surface agents. The reduced surface energyenjoyed by coatings produced from the present composition allow for theexclusion of release agents or surface agents. In addition, the presentradiation-curable composition may be free of non-reactive diluents, suchas water or organic solvents, which lack ethylenic unsaturation.

In preferred embodiments, the radiation-curable composition is used as acolored coating for a telecommunication element, such as an opticalfiber or a telecommunication cable containing optical fibers.

Telecommunications cables containing optical fibers come in a variety ofconfigurations. In some cables, the optical fibers are held looselyinside a buffer tube.

In other cables, the optical fibers are arranged in a planar array toform an optical fiber ribbon. The planar array is typically encapsulatedby one or more radiation-curable matrix material layers. Theradiation-curable matrix layers are cured by exposing the matrixmaterial to ultraviolet radiation, electron beam radiation, ionizingradiation or infrared radiation for a predetermined period of timedeemed suitable for effective curing.

An optical fiber may comprise a core, a cladding and one or morepolymeric coatings applied over the cladding. In particular, an opticalfiber is usually coated with two superposed coatings, although it may becoated with three or more superposed coatings. The coating whichcontacts the glass is a relatively soft, primary coating that mustsatisfactorily adhere to the fiber and be soft enough to resistmicrobending, especially at low service temperatures. An outer, exposedcoating may be a much harder secondary coating, and may provideresistance to handling forces, while possessing sufficient flexibilityto enable the coated fiber to withstand repeated bending withoutcracking the coating.

Thus, the present composition may be tailored to serve as, e.g., acoating for an optical fiber ribbon, a primary or secondary coating foran optical fiber, or even as the tertiary coating for an optical fiber.In still other embodiments, the composition may be used as the lonecoating on an optical fiber.

Because the reactive dye concentrates itself towards the surface of thecoating, a reduced amount of dye is needed to color the fiber. Forexample, a radiation-curable composition according to the invention mayemploy from about 0.1 wt % to about 15 wt %, e.g., from about 1 wt % toabout 12 wt %, of the present fluorinated, radiation-curable reactivedye, based on the total weight of the composition.

An additional advantage of an optical fiber coated with the presentcomposition is that it spools easier.

The technique for coating an optical fiber with the present compositionmay involve a draw tower in which a preformed glass rod is heated toproduce a thin fiber of glass. The fiber is pulled vertically throughthe draw tower and, along the way, the fiber passes through one or morecoating stations at which various coatings are applied and cured in-lineto the newly drawn fiber. The coating stations may each contain a diehaving an exit orifice that is sized to apply the particular coating tothe fiber in a desired thickness. Monitoring and measuring devices maybe provided near each station to ensure that the coating applied at thatstation is coated concentrically and to the desired diameter. Examplesof optical fiber coating techniques that may be utilized in the presentinvention include the methods disclosed in U.S. Pat. Nos. 4,512,281,4,531,959, 4,539,219, 4,792,347, and 4,867,775.

Alternatively, the composition may be formulated to serve as aprotective, colored coating for a wide variety of other substrates,including, for example, glass, plastic, ceramic, metal, wood, andtextiles. For example, the composition may be employed as an ink,coating or colorant package in the printing and inking industries, whenit is desired to replace traditional pigments with dye materials in aradiation-curable, e.g., uv-curable, vehicle. The amount of reactive dyeaccording to the invention in coating, ink, or colorant packageembodiments is not particularly limited, especially in view of thediverse applications in which the reactive dye may be employed. Indeed,while in some of these alternative applications, the reactive dye may bepresent in a composition in an amount of from about 0.1 wt % to about 15wt %, in other applications the dye may make-up an even higherpercentage of the composition, such as from 10-50 wt % of theradiation-curable composition, e.g., from about 15-35 wt % of thecomposition.

Other components of the ink, coating, or colorant package may includeradiation-curable monomers and oligomers, or multifunctionalradiation-curable materials, photoinitiator(s), stabilizer(s),surfactant(s), waxes, etc. in order to adjust viscosity and flowcharacteristics for the desired application.

The ink, coating, or colorant package may be applied to a substrate by anumber of methods, including printing methods, such as gravure printing,ink jet printing, etc. The resulting ink, coating, or colorant packagemay have a number of unique properties, including a high surface energyfinish and non-soiling properties. In short, the composition may providean alternative to traditional methods for providing a non-soilingsurface, such as a method that provides an overcoat of polyvinylidenefluoride (PVDF).

While the invention has been described in detail and with reference tospecific embodiments thereof, it will be apparent to those of ordinaryskill in the art that various changes and modifications can be madetherein without departing from the spirit and scope thereof.

1. A radiation-curable composition, comprising a reactive dye comprisingat least one radiation-curable substituent and at least onefluorine-containing substituent, wherein the composition furthercomprises one or more of a (meth)acrylate urethane oligomer, aphotoinitiator, and one or more process additives selected from thegroup consisting of adhesion promoter, antioxidant, flow control agent,sensitizer, stabilizer, lubricant, and wetting agent.
 2. Theradiation-curable composition of claim 1, wherein the dye is aderivative of an anthraquinone dye, a methine dye, an azo dye, an azinedye, or a xanthene dye, and the dye comprises at least oneradiation-curable substituent and at least one fluorine-containingsubstituent.
 3. The radiation-curable composition of claim 1, whereinthe at least one radiation-curable substituent and the at least onefluorine-containing substituent are two different substituents.
 4. Theradiation-curable composition of claim 1, wherein the at least oneradiation-curable substituent and the at least one fluorine-containingsubstituent are the same substituent.
 5. The radiation-curablecomposition of claim 1, wherein at least one radiation-curablesubstituent contains ethylenic unsaturation.
 6. The radiation-curablecomposition of claim 1, wherein at least one radiation-curablesubstituent is selected from the group of substituents consisting of(meth)acrylate, styrene, vinyl ether, vinyl ester, N-substitutedacrylamide, N-vinyl amide, maleate ester, and fumarate ester.
 7. Aradiation-curable composition, comprising a reactive dye comprising atleast one radiation-curable substituent and at least onefluorine-containing substituent; wherein at least one radiation-curablesubstituent is an epoxy-, thiol-ene-, or amine-ene-containingsubstituent.
 8. The radiation-curable composition of claim 1, whereinthe composition comprises from about 0.1 wt % to about 15 wt % of thereactive dye.
 9. A method for reducing the surface energy of aradiation-curable composition, comprising the step of incorporating areactive dye comprising at least one radiation-curable substituent andat least one fluorine-containing substituent into a compositioncomprising one or more of an oligomer, a photoinitiator, a reactivediluent and one or more process additives selected from the groupconsisting of adhesion promoter, antioxidant, flow control agent,sensitizer, stabilizer, lubricant, and wetting agent.